Electric toothbrush



July 22, 1969 A. R. SPOHR 3,456,276

ELECTRIC TOOTHBRUSH Filed Oct. 10. 1966 2 Sheets-Sheet l @QMYZM United States Patent 3,456,276 ELECTRIC TOOTHBRUSH Albert R. Spohr, Park Ridge, 111., assignor to Sunbeam Corporation, Chicago, 11]., a corporation of Illinois Filed Oct. 10, 1966, Ser. No. 585,457 Int. Cl. A46!) 13/00 U.S. Cl. -22 14 Claims ABSTRACT OF THE DISCLOSURE An electric toothbrush having a power handle from which a drive shaft extends and on which shaft a toothbrush attachment is releasably securable. A release mechanism is attached to the handle near the drive shaft and includes a button which when pressed causes the attachment to be unfastened from the shaft.

This invention relates to an electric toothbrush and more particularly to an improved electric toothbrush of the type having a power handle which is adapted for use with a plurality of brush attachments.

In recent years, the electric toothbrush has gained wide acceptance and popularity in this country because of its ability to perform an exemplary tooth cleaning operation. Most, if not all, commercial electric toothbrushes are offered with a power handle containing an electric motor and a power transmission means which relates the motor to a drive shaft extending from the power handle and with a plurality of brush attachments which are adapted to fasten to the drive shaft. By this arrangement, each member of the household may have his or her own separate brush attachment. However, each attachment can be powered by a single power handle. Thus, it is necessary to purchase only one power handle which may be used with one brush attachment purchased for each memher in the household who intends to use the electric toothbrush.

Inasmuch as the power handle drive shaft is designed to operate at a relatively high speed, it is necessary for the connection between the power handle drive shaft and the brush attachments to be rather sturdy so that the attachments do not become loose in operation. Moreover, a loose connection would undoubtedly cause rapid wear and, consequently, further reduce the effectiveness of the connection. To overcome this problem, it is customary for the brush attachments to be tightly fitted to the drive shaft to insure proper operating performance and a long service life for the attachment.

While a tight connection between the power handle drive shaft and the brush attachment overcomes one roblem, it presents another since, in many instances, the attachment is difficult to remove from the power handle. The removal force is not sufiicient to present much of a problem to an adult user but does cause a difficulty for a child. It should be appreciated that the electric toothbrushes are particularly advantageous for the proper dental hygiene of children who normally do not possess the necessary dexterity with their hands, the patience or inclination for adequate tooth brushing using a manual brush. Thus, it would be a considerable improvement if an electric toothbrush could be provided wherein the brush attachment is rigidly connected to the power handle and the connection therebetween could easily be released by both adults and children. Preferably, the disconnecting arrangement should not appreciably increase the manufacturing cost of the power handle nor increase the likelihood of moisture or contaminants gaining entrance within the handle housing causing deterioration of the internal components.

:It is accordingly an object of the present invention to "ice provide a new and improved electric toothbrush having means for readily disconnecting the brush attachment from the power handle.

Another object of the present invention is to provide an improved electric toothbrush having a brush releasing mechanism which is operated by depressing a button.

A further object of the present invention is to provide an improved electric toothbrush having means for easily disconnecting the brush attachment from the power handle and this means assisting in preventing moisture and other contaminants from entering into the toothbrush.

Still another object of the present invention is to provide an electric toothbrush having means for easily detaching the brush attachment from the power handle which means is low in cost and easily assembled.

Yet another object of the present invention is to provide an electric toothbrush having means for readily removing the brush attachment from the power handle wherein the releasing force is exerted axially with respect to the drive shaft.

Further objects and advantages of the present invention will become more apparent as the following description proceeds and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the present invention, reference may be had to the accompanying drawings in which:

FIG. 1 is a perspective view of an electric toothbrush embodying the present invention;

FIG. 2 is a fragmentary enlarged sectional view taken substantially along line 22 of FIG. 1 illustrating the brush attachment in power transmitting engagement with the handle drive shaft;

FIG. 3 is a fragmentary sectional view taken substantially along line 33 of FIG. 2;

FIG. 4 is a top plan view of the subject toothbrush with the brush attachment and housing cap removed; and

FIG. 5 is a sectional view taken substantially along line 55 of FIG. 4 with the brush attachment being disengaged from the drive shaft.

Briefly, the electric toothbrush of the present invention includes a hand held power handle housing containing an electric motor and a drive shaft which is in driving relationship therewith and which extends through one end of the housing. The exposed end of the drive shaft is provided with connection means which is adapted for receiving in locking and driving relationship a suitable brush attachment. The housing includes a release arrangement for disconnecting the brush attachment from the drive shaft and this arrangement has a button portion which projects through an opening in the housing so that the depression of the button portion releases the attachment from the drive shaft.

Referring now to the drawings in which like numerals designate like parts throughout the several views, the electric toothbrush is generally designated by the reference numeral 20. As may be easily seen in FIGS. 1 and 2, the toothbrush 20 includes a brush attachment 21 which is releasably connected to power handle 22 which is sutficiently small to be easily held in the users hand during the teeth cleaning operation. The power handle 22 includes an elongated housing 24 containing a suitable electric motor 25, a drive shaft 27 journalled at one end in a bearing 29 and a power transmission means 28 between the drive shaft 27 and the motor 25 so that these two members are in driving relationship. Preferably, the motor 25 is supplied with electrical power from a battery (not shown in the drawings) which is also disposed within the housing 24. Inasmuch as the present invention is not directed to the details of the internal power handle construction, they will not be fully disclosed herein. However, the preferred construction of the power handle is disclosed in U.S. Patent No. 3,274,631 which issued Sept. 27, 1966, to the same assignee as in the present application. It should be appreciated that the motor is controlled by switch assembly which is disposed near the end of housing 24 from which the drive shaft 27 emanates so that the switch assembly is easily controlled by the user during the teeth cleaning operation. Inasmuch as it is expected that the toothbrush will be subjected to a considerable amount of moisture and contaminants during the tooth brushing operation, the switch assembly 30 is constructed to prevent the entrance of these mate rials therethrough. Similarly, a seal 32 is positioned adjacent to bearing 29 and at the opening in the housing 24 through which the drive shaft 27 projects. The seal 23 is preferably fabricated from a flexible material such as rubber, so that the movement of the drive shaft 27 does not jeopardize the integrity of this moisture barrier. In the present embodiment, the power transmission means 28 converts the rotary motion of the electric motor 25 into oscillatory motion for the drive shaft 27. Thus, in operation, the drive shaft 27 oscillates and the seal 32 is sufficiently resilient to accommodate the drive shaft motion.

In order that the brush attachment 21 may be rigidly attached to the drive shaft 27, the exposed end of the drive shaft is fabricated with a connection section 35 including tongue portion 36, a cylindrical portion 37 and a groove portion 38. This construction is essentially the same as disclosed in U.S. Patent No. 3,187,360 which issued June 8, 1965, with the exception that the cylindrical portion 37 is somewhat reduced in diameter so that t the brush attachment 21 can be released with only a slight amount of longitudinal movement with respect to the drive shaft 27 as will be explained more completely below.

For the purpose of establishing a drive connection between the brush attachment 21 and the drive shaft 27, the attachment is provided with a cavity 40 including an innermost section 41 having a rectangular cross section conforming to the drive shaft connection section tongue portion 36 whereby the oscillatory motion of the drive shaft is easily imparted to the attachment. In addition, the attachment cavity 40 includes radially spaced internal ribs 42 having inwardly projecting protuberances 43 which are adapted to fit into the drive shaft groove portion 38. Therefore, when the brush attachment 21 is in driving relationship with the drive shaft 27 as illustrated in FIG. 2, the drive shaft tongue section 36 is received in the brush innermost section 41 and the internal rib protuberances 43 are disposed in the drive shaft groove 38. It should be appreciated that the brush attachment is molded from a plastic material which is sufficiently resilient to permit the internal ribs 42 and protuberances 43 to bias outwardly in order to permit the protuberances to disengage from the groove 38 when axial force is exerted on the brush attachment in a direction away from the power handle 22. As indicated hereinbefore, very little axial movement is required in order to disengage the protuberances 43 from the groove 38 since the groove 38 is adjacent to the cylindrical portion 37 which has a diameter sufiiciently small so that it is not gripped by protuberances 43. It should be noted that an outermost section 44 of brush attachment cavity 40 has a rather large bore for a purpose hereinafter described.

In accordance with the present invention, there is provided a sleeve which is in sliding relationship on the drive shaft 27 between the seal 32 and the connection section 35. This sleeve 50 includes a cylindrical portion 51 having an annular upper surface 52 and an enlarged portion 54 having a bottom annular surface 55. As can be seen in FIG. 2, the sleeve cylindrical portion 51 is Cal in good sliding relationship with the drive shaft 27 and when the sleeve is in its upper position, the cylindrical portion 51 is nested within the outermost section 44 of the brush attachment cavity 40. Thus, any moisture or contaminants on the brush attachment 21 cannot flow directly onto the drive shaft 27 due to the sleeve 50 being recessed within the brush attachment cavity 40. Moreover, the sleeve portion 54 is sufliciently large to partially receive the seal 32 so that contaminants flowing along the outer surface of the sleeve cannot easily come in contact with the portion of the seal 32 which is in engagement with the drive shaft 27. In comparing FIGS. 2 and 5, it should be appreciated that the upward movement of the sleeve 50 sliding along the drive shaft 27 causes the cylindrical upper surface 52 to abut against the brush attachment internal ribs 42 causing the protuberances 43 to disengage from the groove 38 thereby releasing the toothbrush attachment from the drive shaft 27. Once the protuberances 43 have been dislodged from the groove 38, very little effort is required to remove the brush attachment from the drive shaft 27. In fact, if the toothbrush 20 is inverted after the sleeve has disconnected the protuberances 43 from groove 38, the slight weight of the brush attachment 21 is sufficient to cause the attachment to drop away from the power handle 22.

In order to cause the sleeve 50 to move axially along the drive shaft 27, there is provided a lever at the end of the housing from which the drive shaft projects. The lever 60 includes a knob or button portion 61, a transversely extending trunnion 62 and a bifurcated end including arms 64 and 65. Preferably, the housing 24 is formed with two bearing projections 67 which are adapted to pivotally receive the lever trunnion 62 so that the lever can pivot on an axis running normal to the drive shaft 27. With this construction, the depression of button portion 61 causes the arms 64 and to move upwardly towards the exposed end of the drive shaft 27. The lever 60 is positioned so that the drive shaft 27 and seal 32 are disposed centrally between the arms 64 and 65. Near the end of each lever arm are integral curved protuberances 69 and 70 which lie substantially in a plane passing through the center line of drive shaft 27 and parallel to the axis of the trunnion 62. The upper surfaces of the protuberances 69 and 70 are rounded and come in contact with the sleeve bottom surface 55. Therefore, when lever button portion 61 is depressed, the protuberances 69 and 70 exert approximately equal forces on both sides of the sleeve to slide it towards the brush attachment. It should be appreciated and understood by those skilled in the art that inasmuch as the axial force is being applied to the sleeve on opposite sides of the drive shaft 27, that there is little, if any, tendency for the sleeve to bind along the shaft. Moreover, when the upper surface of the sleeve 52 engages the brush attachment internal ribs 42, equally distributed pressure is exerted on the brush attachment causing it to disengage itself from the drive shaft connection section 35. The application of a substantially axial force upon the brush attachment 21 contributes to a long service life for this piece.

At the end of the housing 24 for receiving the brush attachment 21, there is provided an end cap 74- which partially encloses lever 60, sleeve 50 and drive shaft 27.

Preferably, the housing 24 is formed with a plurality of hook-shaped arms 75 which are designed to lock with a plurality of complementary hook-shaped arms 76 which depend from cap 74. Thus, the cap 74 is retained to the housing 24 by the interlocking between arms 75 and 76. For retaining the lever trunnion 62 in housing bearing projections 67, the cap 74 is formed with a pair of depending arms 77 so that the lever 60 is maintained in a fixed pivotal relationship to the housing 24. The cap 74 is formed with an opening 79 through which the drive shaft 27 and the sleeve cylindrical portion 51 project. However, the opening 79 is sufliciently small so that the sleeve enlarged portion 54 cannot slide therethrough and, consequently, the cap 74 traps the sleeve 50 onto the drive shaft 27. Another opening 80 is formed in the cap for permitting the lever button portion 61 to be accessible. As seen in FIG. 2, the lever button portion 61 and the switch 30 are positioned immediately adjacent to one another. With this construction, the user can operate both the switch 30 and the lever button portion 61 without changing his grip on the power handle 22. Therefore, the user needs to use only one hand in controlling the actuation of switch 30 and the lever knob portion 61 regulating the unfastening of the brush attachment 21 from the drive shaft 27. For the purpose of limiting the pivotal movement of lever 60, the housing 24 is formed with an integral stop projection 81 disposed below the lever button portion 61.

When it is desired to use the toothbrush 20, the user inserts the brush attachment 21 onto the drive shaft 27 so that the attachment protuberances 43 lock into the shaft groove 38. In inserting the attachment on the shaft, the sleeve 50 is forced inwardly which pivots lever 60 so that the button portion 61 projects through the opening 80 in cap 74. When it is desired to release the brush attachment from the power handle, the user merely depresses the lever button portion 61 which forces the sleeve 50 to slide outwardly along the drive shaft 27 so that the attachment protuberances 43 are forced out of the shaft retaining groove 38. In operation, contaminants flowing along the brush attachment are prevented from reaching the seal 32 by the sleeve 50 projecting within the attachment cavity 40 and the seal 32 being positioned within the enlarged portion of sleeve 50.

What is considered new and desired to be secured by Letters Patent of the United States is:

1. An electric toothbrush comprising an elongated housing containing an electric motor, a drive shaft extending through one end of said housing and having an exposed end outside of said housing, and a power transmission means between said motor and shaft so that said motor actuates said shaft; said drive shaft including connection means on said exposed end which is adapted for making a releasable connection with a brush attachment; a sleeve on said drive shaft in sliding relationship therewith; lever means pivotally connected to said housing one end and having a button portion at one end and an ejecting portion at the other end; said lever means ejecting portion positioned to engage with said sleeve and control the sliding movement of said sleeve along said drive shaft; a cap secured to said housing over said lever means, said sleeve and said drive shaft; said cap having a first opening through which said lever means button portion can project and a second opening through which said drive shaft and sleeve can extend whereby the user can actuate said lever means button portion causing said ejecting portion to pivot and engage with said sleeve forcing it along said shaft to contact and force the brush attachment to disconnect from said drive shaft connection means.

2. The electric toothbrush of claim 1 wherein a switch is provided on said housing for controlling the operation of said motor, said switch and lever means button portion being disposed adjacent one another so that the user can actuate both said switch and knob portion without changing their grip on the housing.

3. The electric toothbrush of claim 1 wherein said lever means is provided with an integral trunnion which extends in a direction normal to said drive shaft; said housing one end formed with hearing means to receive said trunnion so that said lever means can pivot with respect to said drive shaft; said cap having depending integral arm means for retaining said trunnion in said bearing means.

4. The electric toothbrush of claim 1 including a brush attachment having a cavity for receiving said drive shaft connection means; said sleeve being provided with a reduced portion which is receivable within said brush attachment cavity when said attachment is connected to said drive shaft thereby reducing the flow of contaminants from said attachment to said drive shaft; a seal between said drive shaft and housing for preventing the entrance of contaminants into said housing; said sleeve having an enlarged portion partially receiving said seal for reducing the amount of contaminants reaching said seal.

5. The electric toothbrush of claim 1 wherein said lever means ejecting portion is provided with a bifurcated end formed by arms extending below said sleeve; said arms having curved protuberances for engaging said sleeve on opposite sides and approximately along a plane passing through the center line of said drive shaft whereby the pivotal movement of said lever means applies balanced axial force on said sleeve so that it can slide freely.

6. The electric toothbrush of claim 1 wherein said housing one end has an integral projection for limiting the pivotal movement of said lever means.

7. An electric toothbrush comprising an elongated housing which is easily held in the hand of the user, said housing containing an electric motor, a drive shaft and power transmission means therebetween, said drive shaft extending through an opening formed in said housing, a flexible seal between said housing and drive shaft for preventing the entrance of contaminants into said housing, a brush attachment formed with a cavity into which said drive shaft is insertable for establishing a releasable connection therebetween, a sleeve slidably received on said drive shaft between said brush attachment and seal so that axial movement of said sleeve away from said housing causes said brush attachment to disconnect from said drive shaft, lever means pivotally attached to said housing and disposed for sliding said sleeve along said drive shaft, said sleeve positioned when said brush attachment is connected to said drive shaft so that a portion thereof extends into said attachment cavity whereby contaminants cannot readily flow from said attachment onto said shaft, the end of said sleeve facing said seal being enlarged to partially receive said seal for reducing the amount of contaminants reaching said seal.

8. The electric toothbrush of claim 7 wherein a cap secured to said housing is provided over said lever means, sleeve, seal and drive shaft for reducing the amount of contaminants reaching said seal.

9. In combination with a housing for an electric toothbrush powered by an electric motor within said housing, a drive shaft actuated by said motor and extending from one end of said housing, said drive shaft being adapted to releasably receive brush means, sleeve means slidable on said drive shaft for abutting the brush means for releasing the connection therebetween, lever means pivotally connected to hearing means on said housing one end and disposed to axially slide said sleeve means on said drive shaft, a cap secured to said housing and partially overlying said lever means, sleeve means and drive shaft, said cap having depending member retaining said lever means in said housing bearing means, said lever means being accessible through said cap so that the user can actuate said lever means to release the connection between said drive shaft and the brush means.

10. The combination of claim 9 wherein said housing one end is formed with a projection for limiting the pivotal movement of said lever means, said lever means having a button portion which is projectable through an opening defined by said cap, said sleeve means being sufficiently long so that the insertion of the brush means on said drive shaft causes said sleeve means to slide on said drive shaft sufficiently to engage and pivot said lever means whereby said button portion is positioned through said cap opening.

11. In an electric toothbrush comprising a small housing which is adapted to be held in the hand of the user, a drive shaft extending from said housing, said drive shaft being provided with releasable locking means for receiving brush means, lever means pivotally secured to said housing for removing the brush means from said shaft,

said lever means including bifurcated arms extending on opposite sides of said drive shaft whereby the pivotal movement of said lever means causes said arms to move sufiiciently in a direction parallel to said drive shaft so that balanced axial forces can be applied to said brush means for releasing the same from the drive shaft.

12. In the toothbrush of claim 11 wherein a sleeve is slidable on said drive shaft between said lever means arms and the brush means, said lever means arms being provided with protuberances which engage said sleeve on opposite sides of said drive shaft, said sleeve having an annular surface normal to said drive shaft for engaging the brush means so that balanced axial forces 'are exerted upon the brush means during releasement.

13. In an electric toothbrush of the type employing a power actuated brush attachment comprising an elongated housing which is sufiiciently small to be held in the hand of the user, said housing containing a motor and a drive shaft which is in driving relationship with said motor and which extends through one end of said housing, said drive shaft having connection means at its exposed end, said connection means adapted for receiving in locking and driving relationship the brush attachment, release means secured to said housing for disconnecting the brush attachment from said drive shaft connection means, said release means including a button portion which projects through an opening in said housing, a switch being secured to said housing for controlling said motor, said switch and button portion being disposed adjacent one another, said release means including lever means pivotally secured to said housing one end, said lever means including said button portion at one end and ejecting portion at the other end thereof whereby when said button portion is depressed said ejecting portion pivots in such a manner as to cause unlocking between said drive shaft connection means and the brush attachment, and the user can operate both said switch and said button portion without changing their grip on said housing.

14. In an electric toothbrush of the type employing a power actuated brush attachment comprising an elongated housing which is sutliciently small to be held in the hand of the user, said housing containing a motor and a drive shaft which is in driving relationship with said motor and which extends through one end of said housing, said drive shaft having connection means at its exposed end, said connection means being adapted for receiving in locking and driving relationship the brush attachment, release means secured to said housing for disconnecting the brush attachment from said drive shaft connection means, said release means including button means which projects through an opening in said housing and lever means pivotally secured to said housing one end, said button means being disposed for pivoting said lever means, said release means including an ejection means positioned adjacent to said drive shaft and moved by the pivoting of said lever means whereby when said but-ton means is depressed said ejection means moves in such a manner as to cause unlocking between said drive shaft connection means and the brush attachment.

References Cited UNITED STATES PATENTS 3,027,585 4/1962 Freedman et al. 3,162,876 12/1964 Aronson et al. 15-28 3,289,231 12/1966 Minton et al. -a 15-28 EDWARD L. ROBERTS, Primary Examiner US. Cl. X.R. 259-l 

